Method and a device for making brush-strips



Nov. 5, 1957 nsANDELlN 2,812,214-

METHOD'AND ADEVICE FOR MAKING BRUSH-STRIPS Filed June 17, '1953 2 Sheets-Sheet 1 www l/f/ f/ Nov. 5, 1957 P. sANpELlN 2,812,214

METHOD AND A DEVICEV'FOR MAKING BRUSH-STRIPS Filed -Jun .1?, 1953 2 Sheets-Sheet 2 United States Patent() y Applicatie June 17, 195s, serial No. 362,294 y Y Claimspriority, application Sweden June 21, 1952 4v Claims. (Cl. 30o-21) This invention relates to` a method and aV device for making brush-strips of the kind where the bristles are fastened within a groove-shaped holder. p

According toa-knownv construction the holder has been `made yof a cut metal strip, which has been bent to ,thesectional formy of a U. The, bristles have been maintainedin the holder only by friction owing to the pressure from the side walls of the holder, which has been found to be insufficient. The bristles have also been damaged by wear against the sharp edges of the metal strips.

An object of the invention is to have the bristles more rigidly secured to the holder.

Another object is to provide a holder which cannot wear against the bristles.

A further object of the invention is to manufacture the holder and fasten the bristles therein in a single continuous operation.

With these and other objects in view the invention is hereinafter described and illustrated by way of example in the accompanying drawing, in which:

Figure'l is a perspective View of the main parts of the fore end of an extrusion press according to one form of the invention, t

Figure 2 is a vertical section of the brush-strip shown in Fig. 1 including a feeding device omitted in Fig. l. Figure 3 is a side view of a modified form of the invention.

The fore portion 1 of an extrusion press is provided with a mouth-piece or die of such a form that a preferably somewhat groove-shaped strip is formed when heated plastic or the like is pressed through the die. From the die the strip passes through a groove-shaped guide member 2 secured to the mouth-piece and formed principally as a pipe with an upper longitudinal slot 7. This pipe serves to guide the soft strip and to bend the same to a holder 3 with a U-shaped cross section. The slot in the member 2 is wider and its edges are lower in the rear portion than in the fore portion for the purpose described below.

The bristles 4 to be introduced in the guide member 2 and fastened to the holder 3 may be conveyed by means of an endless belt or in a similar way to the mouth-piece 2 and form a ribbon with the bristles arranged transversally to the feed direction. A thread 5 of metal, plastic or other material is fed together with the ribbon thereby maintaining the bristles in order. The bristle ribbon is brought onto the guide member 2 at the portion, where the slot is widest and its edges are lowest, and during the subsequent feed motion the ribbon passes beneath a stationary guide cam 6, by means of which the thread and thereby also the middle portion of the bristles and the strip are pressed downwards against the bottom of the guide member. The bristles are in this way folded with their ends upwards by the narrowing and raising edges of the slot. The inner cross section of the guide member is continuously reduced in the feed direction so ice as to correspond at the end substantially tothe outline vof the nished holder 3. The side walls of the holder are simultaneously pressed against the bristles which thereby are partly pressed into the soft plastics and adhere thereto. y

It may be of advantage to provide a feed device in front of and at a short distance from the end of the guide member. This feed device may comprise two driven press rollers 8 and 9 one on each sideV of the holder 3 and of such section of the peripheral surface that the holder obtains its final desired shape.' The rollers 8, 9, are driven from a shaft 10 by means of a gear. Thenished holder 3 will better maintain its shape, if the 'temperature is lowered to a certain extent in dependence of the material used, and for this reason the guide member may be cooled by means of a suitable water cooling device. j

The xed guide cam 6 has such a peripheral curve form that the bristle ribbon is successively depressed and introduced `into the curved strip and the edge of theV cam may have aperipheral groovefor guidingl the thread. p According to Figure 3 the pressing member forms a freely rotating wheel 11 for pressing the metal wire 5 and the bristle ribbon 4 against the strip so that friction between the wheel 11 and the ribbon is avoided. The bristles are delivered from a hopper indicated at 12 upon two parallel endless belts 13 passing each at one side of the guide member 2. The belts pass over pairs of pulleys 14, 15, 16, 17, 18. The shaft 19 carries between the pulleys 15 a roller 20 reaching to the upper surface of the belts 13. The wire 5 is drawn from a drum 21 over a roller 22 so that the wire 5 rests on the sloping bristle ribbon 4 and keeps the bristles in order. The roller 22 is driven and drives the shaft of the pulleys 15 by a transmission 23 and thereby the belts 13.

According to the drawing the bristles are fastened in the holder at their middle portions, which are secured in their positions by adhering to the plastics and by the thread 5, but it is obvious, that the bristles also may be bent near one end and clamped by the strip so that only a single row of bristles extends from the holder. This arrangement is of advantage especially in case pig bristles are used as their thickness decreases from the root-end towards the top. Also other modifications are possible, however, without departing from the principle of the invention.

I claim:

l. A method of making brush-strips with bristles fastened within a groove-shaped holder, comprising the steps of pressing a heated plastic through a mouth-piece to form a continuous and solid strip, feeding a ribbon of transversely arranged bristles over said strip during the passage of the strip through the mouth-piece with the bristles located transversely of the strip, pressing the bristles against the strip, bending the opposite edges of the strip and simultaneously the opposite portions of the bristles upwards and towards each other so as to clamp the bristles and cause the bristles to be partly pressed into the soft plastic and to adhere thereto, and drawing the brush-strip thus formed out of the mouth-piece.

2.,A method of making brush-strips with bristles fastened within a groove-shaped holder, comprising the steps of pressing a heated plastic through a mouth-piece to form a continuous and solid strip,l feeding a ribbon of transversely arranged bristles and a thread upon and along said ribbon over said strip during the passage of the strip through the mouth-piece with the bristles located transversely of the strip, pressing the bristles and the thread against the strip, bending the opposite edges of the strip and simultaneously the opposite portions of the bristles upwards and towards each other so as to clamp the bristles and the thread and to cause the bristles to be partly pressed into the soft plastic and to adhere thereto, and drawing the brush-strip thus formed out of the mouthpiece. 3. In `a device for making brush-strips with bristles` fastened within a groove-shaped holder, an extrusion press for extruding heated plastic to form a continuous strip, a tube-shaped guide member for said strip mounted onsaid press and having an upper longitudinal slot, a press member located above said guide member and extending through said slot, a feeding device for feeding a ribbon of transversely arranged bristles between the strip and said press member,` said tube-shaped guide member having an innerwall with the edges along said slot converging in the feed direction 'for bending the opposite edges. of the strip and simultaneously the opposite portions of the bristles upwards and towards each other for c1ampingthe bristles and causing them to be partly pressed into the soft plastic and to adhere thereto, and two driven press rollers in front of and at a distance from said guide member for feeding the brush strip between them and out of said guide member.

4. In a device for making brush-strips with bristles fastened within a groove-shaped holder, an extrusion press for extruding heated plastic to form a continuous strip, a tube-shaped guide member lfor said strip mounted on said press and having an upper longitudinal slot, a rotary press member located above said guide member and extending through said slot, a feeding device for feeding a ribbon of transversely arranged bristles and a thread upon and along saidribbon between the strip and said press member, saidV tube-shaped `guide member having an inner wallwith the edgesalong said slot converging `in the feed direction for bending the opposite edges of the strip and simultaneously the opposite portions of the bristles upwardsgaud towards each other for clamping the bristles with the thread and causing the bristles to be partly pressed into the soft plastieand to adhere thereto, and two driven press rollers in front of and at a distance from said guide member for feeding the brush strip between them and out `of said guide member.

References Cited in the le of this patent UNITED STATES PATENTS 1,322,464 Oden Nov. 18, 1919 1,824,649 Angell Sept, 22, 1931 1,963,045 Bickel June 12, 1934 2,035,709 Laub Mar. 31, 1936 

